First this was part of the Ghana Empire after the domestication of the camel allowed African tribes to trade and flourish.

Then it became the medieval Sosso kingdom, then the Mali Empire, then the Songhai Empire, one of the largest Islamic empires in history, which fell to Moroccan invaders who dissolved the area into smaller kingdoms.

France invaded in 1898. In 1957 Guinea voted for independence, and the French colonists and much of the infrastructure and money left. Guinea went with Soviet Russia and China, and capitalist countries like the US carried on helping it too.

Sékou Touré was the one-party leader and a bit mad, flitting between US/USSR support and imprisoning/exiling/executing opponents. After Touré died, Lansana Conté took power, turned away from socialism and freed some political prisoners. Recently the country has been affected by West African instability.